Microwave Pre-Chamber Ignition for Lean Combustion Stability
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Solution Overview
Problem
Existing pre-chamber ignition systems in internal combustion engines suffer from high heat losses, poor cold start capacity, erratic operation under low load conditions, and inefficiencies in lean and ultra-lean combustion due to poor ignition quality and flammability, particularly with passive systems, and high costs with active systems.
Innovation Solution
A pre-chamber ignition apparatus utilizing a microwave ignition device with an antenna to generate microwaves for igniting the air/fuel mixture, combined with a plasma ignition device, and a simplified fuel injector, to enhance combustion efficiency and flammability, especially under lean conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a passive pre-chamber ignition system is used, then combustion speed increases and detonation is prevented, but heat losses increase and cold start capacity deteriorates
Solution Approach 1:
The patent replaces the conventional mechanical spark ignition system with a microwave-based ignition system. The microwave generator produces electromagnetic radiation that directly ionizes the air-fuel mixture in the pre-chamber, eliminating the need for mechanical spark plugs and associated electrical components. This substitution enables reliable ignition even under extreme conditions while reducing heat losses to chamber walls.
Solution Approach 2:
The patent changes the ignition mechanism from electrical spark to microwave radiation. By using electromagnetic radiation in the microwave frequency range, the system achieves plasma formation and ignition through dielectric heating and electron avalanche effects, fundamentally altering the ignition parameters to overcome limitations of conventional systems.
2Use of energy by moving object
If lean and ultra-lean combustion is implemented, then engine efficiency increases, but ignition quality deteriorates and combustion becomes erratic
Solution Approach 1:
The microwave ignition system replaces conventional spark plugs, generating intense electromagnetic fields that directly ionize ultra-lean air-fuel mixtures. This substitution enables reliable ignition of mixtures with very low fuel concentrations that would otherwise fail to ignite or burn erratically with traditional electrical spark systems.
Solution Approach 2:
The patent changes the ignition approach by using microwave radiation instead of electrical sparks. The electromagnetic radiation provides sufficient energy density to initiate combustion in ultra-lean mixtures, fundamentally changing the ignition parameters to enable efficient operation at very low fuel-to-air ratios.
3Reliability
If an active pre-chamber system with additional GDI injector is used, then flammability improves, but system cost increases
Solution Approach 1:
The patent extracts and eliminates the complex fuel injection system from the pre-chamber configuration. By using microwave ignition, the system can operate with simple passive pre-chambers that rely on diffusion and turbulence for fuel-air mixing, removing the need for additional GDI injectors, high-pressure fuel rails, and associated control systems.
Solution Approach 2:
The microwave ignition system replaces the need for active fuel injection into the pre-chamber. The electromagnetic radiation provides such effective ignition that complex mechanical injection systems can be eliminated, substituting a relatively simple microwave generator for complex multi-component fuel delivery systems.
4Reliability
If conventional spark plug is used in pre-chamber, then ignition is achieved, but performance deteriorates under high EGR and cold conditions
Solution Approach 1:
The patent replaces conventional spark plugs with a microwave ignition system. The microwave generator produces electromagnetic radiation that directly ionizes the air-fuel mixture through dielectric heating and electron avalanche, providing reliable ignition in cold conditions and under high EGR where conventional spark plugs fail due to insufficient energy and poor mixture preparation.
Solution Approach 2:
The patent changes the ignition mechanism from electrical spark to microwave radiation, fundamentally altering the energy delivery parameters. The microwave system provides sustained electromagnetic field exposure that ensures reliable ignition under extreme conditions where conventional spark timing and energy levels are insufficient.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system improves combustion efficiency and flammability, extends the operating range of internal combustion engines to lean and ultra-lean mixtures, reduces costs, and simplifies installation by integrating with existing engine architectures without requiring redesign.
Implementation Method 1
a microwave ignition device, equipped with an antenna configured to generate microwaves suitable to ignite an air/fuel mixture in a pre-chamber inside the housing
Implementation Method 2
The downstream portion is provided with the at least one connection hole, wherein the hollow downstream portion includes a reflection wall opposite the microwave ignition device and shaped to receive and concentrate the microwaves generated by the latter
Implementation Method 3
a resonance cavity for the mixture contained in the pre-chamber thereby amplifying the pre-chamber combustion
Implementation Method 4
an antenna configured to generate microwaves suitable to ignite an air/fuel mixture in a pre-chamber
Data Source
AI summary
A pre-chamber ignition apparatus for an internal combustion engine comprising an apparatus body associable with the cylinder head of an internal combustion engine for communicating with a combustion chamber of the cylinder head through at least one connection hole, a microwave ignition device for generating microwaves to cause ignition of an air/fuel mixture in a pre-chamber formed within the apparatus body. The apparatus body comprises an upstream portion configured to allow the housing and fixing of the microwave ignition device and a hollow downstream or head portion, delimiting the pre-chamber, in fluid communication with the combustion chamber. The downstream portion is provided with at least one connection hole. The hollow downstream portion includes a reflection wall opposite the microwave ignition device and shaped to receive and concentrate microwaves generated by the microwave ignition device and/or a resonance cavity for the mixture contained in the pre-chamber thereby amplifying the combustion in the pre-chamber.